The Diabetes Prevention Program Outcomes Study is studying the long term effect of diet and exercise and the diabetes medication, metformin, on the delay of type 2 diabetes in participants of the Diabetes Prevention Program (DPP). The DPPOS is the long-term follow-up phase of the Diabetes Prevention Program (DPP). The DPP was a randomized clinical trial that showed that type 2 diabetes could be prevented or delayed in high risk individuals by the drug metformin or by an intensive behavioral weight loss program. The original DPP participants are followed in the DPPOS to determine ifthese interventions will have long-term benefits on the development diabetes, microvascular and macrovascular complications, and other health measures.